Valve assembly for reciprocating compressors

ABSTRACT

A valve assembly for the reciprocating compressors, elements of which are easily assembled into a single body, and which reduces impact and noise caused by an operation of a reed valve, thus allowing a silent operation of the reciprocating compressors. The valve assembly includes an exhaust hole plate having an exhaust hole, a reed valve plate having a reed valve, a stopper plate having a stopper, and a pressure unit formed on a surface of a cylinder head. The exhaust hole plate, the reed valve plate and the stopper plate are assembled with the cylinder together with the cylinder head when the cylinder head is mounted to the cylinder. The stopper is bent at a junction end thereof at a predetermined angle of inclination, so that a free end of the stopper is raised toward the cylinder head. The free end of the stopper is bent toward the cylinder head, thus providing an elastic support part. The pressure unit includes a first pressure projection to compress the junction end of the stopper, a second pressure projection to compress the elastic support part of the stopper, and a third pressure projection to compress an intermediate point of the stopper between the junction and free ends. The stopper is thus supported while being bent into a bow shape at a position between the cylinder head and the exhaust hole plate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.2003-77227, filed Nov. 3, 2003 in the Korean Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates, in general, to reciprocating compressorsand, more particularly, to a valve assembly for the reciprocatingcompressors, elements of which are easily assembled into a single body,and which reduces operational impact and noise caused by an operation ofa reed valve, thus allowing a silent operation of the reciprocatingcompressors.

2. Description of the Related Art

Generally, a conventional reciprocating compressor includes a pluralityof elements which are a stator, a rotor, a crankshaft, a cylinder, apiston and a cylinder head. The above-mentioned elements arehermetically housed in a hermetic casing. The stator and the rotor areinstalled in the hermetic casing such that the stator is immobile, whilethe rotor is rotatable. The crankshaft axially penetrates through therotor to rotate along with the rotor in response to an electromagneticaction between the stator and the rotor when the compressor is turned onas a result of electricity being supplied. The cylinder defines achamber therein to draw and then compress a gas in the chamber, whilethe piston is received in the cylinder so as to execute a rectilinearreciprocating motion in the cylinder, in response to a rotation of thecrankshaft. The cylinder head covers a top of the cylinder. During anoperation of the conventional reciprocating compressor, the pistonrectilinearly reciprocates in the cylinder in response to the rotationof the crankshaft, thus drawing a gas into the cylinder inside thehermetic casing, and then compressing the gas, prior to releasing thecompressed gas under high pressure from the cylinder to an outside ofthe hermetic casing. The conventional reciprocating compressor havingthe above-mentioned construction is preferably used in a refrigerationsystem, such as a refrigerator or an air conditioner, so as to compressa gas refrigerant under low pressure to make the gas refrigerant underhigh pressure.

In the conventional reciprocating compressor, a valve assembly isinterposed between the cylinder and the cylinder head so as to controlboth low-pressure gas suction into the cylinder inside the hermeticcasing and high-pressure gas exhaust from the cylinder to the outside ofthe hermetic casing, during the operation of the reciprocatingcompressor.

A conventional valve assembly for reciprocating compressors includes anexhaust valve unit having a reed valve, a stopper and a keeper. The reedvalve controls the gas exhaust from the cylinder to the outside of thehermetic casing, while the stopper limits an opening ratio of the reedvalve within a predetermined range. The keeper supports the stopper. Thereed valve, the stopper and the keeper of the exhaust valve unit aresequentially assembled on an exhaust hole plate which has both a suctionhole and an exhaust hole. The exhaust hole plate having the exhaustvalve unit is set together with a suction valve plate integrally havinga suction valve, at a position between the cylinder and the cylinderhead by use of a plurality of locking members, such as bolts.

When the piston is moved from a lower dead center to an upper deadcenter in the cylinder, the gas is compressed in the cylinder. Apressure of the compressed gas is thus applied to the exhaust hole, sothat a free end of the reed valve is elastically bent along with thestopper toward the cylinder head, thereby opening the exhaust hole. Thecompressed gas under high pressure is thus released from the cylinder tothe outside of the hermetic casing through both the cylinder head andthe open exhaust hole. When the piston is moved from the upper deadcenter to the lower dead center in the cylinder, the reed valveelastically closes the exhaust hole, due to a restoring force of boththe stopper and the reed valve, and, at the same time, the suction valveof the suction valve plate is opened to draw the gas under low pressureinto the cylinder through both the open suction hole and the cylinderhead.

However, the conventional valve assembly for reciprocating compressorsis problematic, as follows. In the conventional valve assembly for thereciprocating compressors, the reed valve to control the exhaust hole,the stopper to limit the opening ratio of the reed valve within thepredetermined range, and the keeper to support the stopper areseparately produced, and are sequentially assembled on the exhaust holeplate. Therefore, the reed valve, the stopper and the keeper must besequentially assembled on the exhaust hole plate, before the exhausthole plate is set between the cylinder and the cylinder head by use ofthe plurality of bolts. Thus, excessive time is consumed whileassembling the reed valve, the stopper and the keeper into the valveassembly.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide a valveassembly for reciprocating compressors, elements of which are easilyassembled into a single body.

It is another aspect of the present invention to provide a valveassembly for reciprocating compressors, which reduces operational impactand noise caused by an operation of a reed valve, thus allowing a silentoperation of the reciprocating compressors.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

The above and/or other aspects are achieved by providing a valveassembly for reciprocating compressors having a cylinder, a cylinderhead and a valve assembly arranged between the cylinder and cylinderhead, the valve assembly including: an exhaust hole plate having anexhaust hole communicating with the cylinder; a reed valve plate havinga reed valve to open or close the exhaust hole of the exhaust holeplate, the reed valve being integrally formed in the reed valve plate bycutting a predetermined portion of the reed valve plate, with a junctionend and a free end formed at first and second ends of the reed valve,respectively; a stopper plate having a stopper to limit an opening ratioof the reed valve within a predetermined range, the stopper beingintegrally formed in the stopper plate by cutting a predeterminedportion of the stopper plate, with a junction end and a free end formedat first and second ends of the stopper, respectively, the stopper beingbent toward the cylinder head at a predetermined angle of inclinationrelative to the stopper plate, with an elastic support part provided atthe free end of the stopper so as to be elastically supported by apressure unit of the cylinder head and provide an elastic force to thestopper; and the pressure unit provided on a surface of the cylinderhead so as to support the stopper and allow the stopper topre-pressurize the reed valve.

The elastic support part may be provided by bending the free end of thestopper toward the cylinder head at a predetermined angle ofinclination.

The pressure unit may include: a first pressure projection projectedfrom the cylinder head at a position corresponding to the junction endof the stopper, thus compressing the junction end of the stopper; asecond pressure projection projected from the cylinder head at aposition corresponding to the elastic support part of the stopper, thuscompressing the elastic support part of the stopper; and a thirdpressure projection projected from the cylinder head at a positioncorresponding to an intermediate point of the stopper between thejunction end and the free end of the stopper, thus compressing theintermediate point of the stopper.

The second pressure projection may be slightly longer than the firstpressure projection, and the third pressure projection may be slightlyshorter than the first pressure projection, so that the first, secondand third pressure projections support the stopper while bending thestopper into a bow shape at a position between the cylinder head and theexhaust hole plate, and the free end of the reed valve ispre-pressurized by the elastic support part of the stopper which iscompressed by the second pressure projection.

The third pressure projection may be eccentrically positioned betweenthe first and second pressure projections, and the exhaust hole may beformed on the exhaust hole plate at a position corresponding to thethird pressure projection.

The third pressure projection may be positioned to be eccentric towardthe second pressure projection.

The valve assembly may further include: a depression formed on a surfaceof the exhaust hole plate at a position around the exhaust hole, so thatthe reed valve closes the exhaust hole while a part of the reed valvecomes into contact with areas of the exhaust hole plate around theexhaust hole and the depression.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe preferred embodiments, taken in conjunction with the accompanyingdrawings of which:

FIG. 1 is a longitudinal sectioned view of a reciprocating compressorhaving a valve assembly, according to an embodiment of the presentinvention;

FIG. 2 is an exploded perspective view of the valve assembly of FIG. 1;

FIG. 3 is a top perspective view of an exhaust hole plate included inthe valve assembly of FIG. 2;

FIG. 4 is a top perspective view of a reed valve plate included in thevalve assembly of FIG. 2;

FIG. 5 is a top perspective view of a stopper plate included in thevalve assembly of FIG. 2;

FIG. 6 is a bottom perspective view of a cylinder head which is includedin the reciprocating compressor of FIG. 1, and is assembled with thevalve assembly of FIG. 2;

FIG. 7 is a sectional view taken along the line A-A of FIG. 2, when thereed valve closes an exhaust hole; and

FIG. 8 is a sectional view taken along the line A-A of FIG. 2, when thereed valve opens the exhaust hole.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the present preferredembodiments of the present invention, examples of which are illustratedin the accompanying drawings, wherein like reference numerals refer tolike elements throughout. The embodiments are described below in orderto explain the present invention by referring to the figures.

FIG. 1 is a longitudinal sectioned view of a reciprocating compressorhaving a valve assembly 20, according to an embodiment of the presentinvention. As shown in FIG. 1, the reciprocating compressor according tothe embodiment of the present invention includes a plurality of elementswhich are a stator 1, a rotor 2, a crankshaft 3, a cylinder 4, a piston6 and a cylinder head 7. The above-mentioned elements of thereciprocating compressor are hermetically housed in a hermetic casing10. The stator 1 and the rotor 2 are installed in the hermetic casing10, such that the stator 1 is immobile, while the rotor 2 is rotatable.The crankshaft 3 is axially inserted into the rotor 2 to rotate alongwith the rotor 2. The cylinder 4 defines a compression chamber therein.The piston 6 is received in the cylinder 4, and is coupled to thecrankshaft 3 via a connecting rod 5. The cylinder head 7 covers a top ofthe cylinder 4.

A gas suction pipe 8 and a gas exhaust pipe (not shown) pass through thehermetic casing 10, and are mounted to the cylinder head 7, so that agas is drawn into the cylinder 4 through the gas suction pipe 8. The gasis then compressed in the cylinder 4, and is released from the cylinder4 to an outside of the hermetic casing 10 through the gas exhaust pipe.The reciprocating compressor further includes the valve assembly 20which is interposed between the cylinder 4 and the cylinder head 7 so asto control both gas suction into the cylinder 4 inside the hermeticcasing 10 and gas exhaust from the cylinder 4 to the outside of thehermetic casing 10 during an operation of the reciprocating compressor.

FIG. 2 is an exploded perspective view showing a construction of thevalve assembly 20, according to the present invention. As shown in FIG.2, the valve assembly 20 includes an exhaust hole plate 30 having anexhaust hole 31, a reed valve plate 40 having a reed valve 41, and astopper plate 50 having a stopper 51. In the valve assembly 20, theexhaust hole plate 30, the reed valve plate 40 and the stopper plate 50are sequentially arranged between the cylinder 4 and the cylinder head7.

The valve assembly 20 also has a gasket 60 and a suction valve plate(not shown). The gasket 60 is closely interposed between the cylinderhead 7 and the stopper plate 50 so as to prevent a gas leakage from ajunction of the cylinder head 7 and the stopper plate 50. The suctionvalve plate (not shown) having a suction valve is arranged under theexhaust hole plate 30, so that the suction valve of the suction valveplate controls a suction hole 32 provided on the exhaust hole plate 30.

The present invention is characterized in that the construction of boththe reed valve and the stopper is improved to accomplish the aspects ofthe invention, so that the suction valve plate is not shown in theaccompanying drawings, and further explanation for the suction valveplate is not deemed necessary.

In the valve assembly 20, all the exhaust hole plate 30, reed valveplate 40, stopper plate 50, gasket 60 and the cylinder head 7 haverectangular designs which are chamfered or rounded at corners thereof.The exhaust hole plate 30, reed valve plate 40, stopper plate 50 and thegasket 60 are provided with a plurality of locking holes 35, 45, 55 and65 at corners thereof. Therefore, the exhaust hole plate 30, reed valveplate 40, stopper plate 50 and the gasket 60 are assembled with eachother when the cylinder head 7 is fastened to the cylinder 4 by use of aplurality of bolts 26. In such a case, the bolts 26 are initiallyinserted into locking holes 25 provided at corners of the cylinder head7, and sequentially pass through the locking holes 65, 55, 45 and 35 ofthe gasket 60, stopper plate 50, reed valve plate 40 and the exhausthole plate 30, prior to being tightened to the cylinder 4.

To compress the stopper 51 at several points and thereby to support thestopper 51 while bending the stopper 51 into a predetermined shape so asto allow the stopper 51 to pre-pressurize a free end 43 of the reedvalve 41, the valve assembly 20 has a pressure unit 70 which is providedon a surface of the cylinder head 7. The construction of the reed valve41, stopper 51 and the pressure unit 70 will be described in detailherein below, with reference to FIGS. 3 to 6.

FIGS. 3 to 5 are top perspective views of the exhaust hole plate 30,reed valve plate 40 and the stopper plate 50 of the valve assembly 20 ofFIG. 2, respectively. FIG. 6 is a bottom perspective view of thecylinder head 7 which is assembled with the valve assembly 20 of FIG. 2.

As shown in FIG. 3, the exhaust hole plate 30 is a flat plate having apredetermined thickness, with one locking hole 35 formed at each of therounded corners of the exhaust hole plate 30. The exhaust hole 31 andthe suction hole 32 are formed in the exhaust hole plate 30, so that thegas is drawn into the cylinder 4 through the suction hole 32 so as to becompressed in the cylinder 4, prior to being discharged from thecylinder 4 to the outside of the hermetic casing 10 through the exhausthole 31.

The exhaust hole plate 30 further includes a depression 33 which isformed on a surface of the exhaust hole plate 30 at a position aroundthe exhaust hole 31. The depression 33 has a size slightly smaller thana size of the reed valve 41 of the reed valve plate 40. Therefore, whenthe reed valve 41 closes the exhaust hole 31, only a part of the reedvalve 41 comes into contact with areas of the exhaust hole plate 30around the exhaust hole 31 and the depression 33. Therefore, a contactarea between the reed valve 41 and the surface of the exhaust hole plate30 is reduced, when the reed valve 41 closes the exhaust hole 31. Theoperational noise of the reed valve 41 is thus reduced.

As shown in FIG. 4, the reed valve plate 40 is a flat plate which isremarkably thinner than the exhaust hole plate 30. One locking hole 45is formed at each of the chamfered corners of the reed valve plate 40.The reed valve 41 is provided in the reed valve plate 40 at a positioncorresponding to the depression 33 including the exhaust hole 31 of theexhaust hole plate 30, thus opening or closing the exhaust hole 31.

The reed valve 41 is integrally formed in the reed valve plate 40 bycutting a predetermined portion of the reed valve plate 40 along aU-shaped line.

The reed valve 41 is thus integrated with a remaining part of the reedvalve plate 40 at a first end thereof at which the reed valve 41 is notcut, so that the first end of the reed valve 41 forms a junction end 42.A second end of the reed valve 41, at which the reed valve 41 isseparated from the remaining part of the reed valve plate 40, forms thefree end 43. The reed valve 41 is elastically bent at the free end 43 soas to open or close the exhaust hole 31.

As shown in FIG. 5, the stopper plate 50 is a flat plate which isremarkably thinner than the exhaust hole plate 30, in the same manner asthat described for the reed valve plate 40. One locking hole 55 isformed at each of the chamfered corners of the stopper plate 50. Thestopper 51, having a size corresponding to the reed valve 41, isprovided in the stopper plate 50 at a position corresponding to the reedvalve 41. The stopper 51 limits an opening ratio of the reed valve 41within a predetermined range, while pre-pressurizing the free end 43 ofthe reed valve 41.

In the same manner as that described for the reed valve 41, the stopper51 is integrally formed in the stopper plate 50 by cutting apredetermined portion of the stopper plate 50 along a U-shaped line. Thestopper 51 is thus integrated with a remaining part of the stopper plate50 at a first end thereof at which the stopper 51 is not cut, and thefirst end of the stopper 51 forms a junction end 52. A second end of thestopper 51, at which the stopper 51 is separated from the remaining partof -the stopper 50, forms a free end 53. The free end 53 of the stopper51 limits the opening ratio of the reed valve 41 within thepredetermined range.

The stopper 51 is also bent at the junction end 52 at an angle θ ofinclination relative to the remaining part of the stopper plate 50, sothat the stopper 51 is raised toward the cylinder head 7. The stopper 51is bent again at the free end 53 thereof at an angle ω of inclinationrelative to a remaining part of the stopper 51, so that the free end 53of the stopper 51 is further raised toward the cylinder head 7 and formsan elastic support part 54. Due to the elastic support part 54, thestopper 51 has a sufficient elastic force capable of efficientlypre-pressurizing the reed valve 41. In the present invention, the anglesθ and ω of inclination of the stopper 51 are preferably set to 90° orless.

When the stopper plate 50 is set in the valve assembly 20 at apredetermined position between the cylinder head 7 and the exhaust holeplate 30, the stopper 51 is compressed at several points thereof by thepressure unit 70 of the cylinder head 7, so that the stopper 51 issupported while being smoothly bent into a bow shape.

As shown in FIG. 6, the pressure unit 70 is provided on the lowersurface of the cylinder head 7 having one locking hole 25 at each of therounded corners thereof. The pressure unit 70 compresses the raisedstopper 51 of the stopper plate 50 at the several points to support thestopper 51 while bending the stopper 51 into the bow shape.

The pressure unit 70 includes first, second and third pressureprojections 71, 72 and 73. The first pressure projection 71 is formed inthe cylinder head 7 at a position corresponding to the junction end 52of the stopper 51. The second pressure projection 72 is formed in thecylinder head 7 at a position corresponding to the elastic support part54 of the stopper 51. The third pressure projection 73 is formed in thecylinder head 7 at a position corresponding to an intermediate point ofthe stopper 51 between the junction end 52 and the free end 53. Thearrangement of the first, second and third pressure projections 71, 72and 73 in the cylinder head 7 will be described in detail herein below,with reference to FIGS. 7 and 8.

FIGS. 7 and 8 are sectional views taken along the line A-A of FIG. 2,when the reed valve 41 of the reed valve plate 40 closes and opens theexhaust hole 31 of the exhaust hole plate 30, respectively.

As shown in FIG. 7, the first and second pressure projections 71 and 72are projected from the lower surface 7 a of the cylinder head 7 towardthe cylinder 4, so that pressure surfaces of the first and secondpressure projections 71 and 72 are embossed on the lower surface 7 a. Inthe above state, the second pressure projection 72 is slightly longerthan the first pressure projection 71. The third pressure projection 73is projected in a depression formed on the lower surface 7a of thecylinder head 7, so that a pressure surface of the third pressureprojection 73 does not reach a level of the lower surface 7 a. That is,the third pressure projection 73 is slightly shorter than the firstpressure projection 71. Therefore, the first, second and third pressureprojections 71, 72 and 73 of the pressure unit 70 compress the junctionend 52, elastic support part 54 and the intermediate point between thejunction and free ends 52 and 53 of the stopper 51, respectively, thussupporting the stopper 51 while bending the stopper 51 into the bowshape.

In other words, the junction end 52 of the stopper 51, which isconnected to the remaining part of the stopper plate 50, is compressedby the first pressure projection 71, thus being secured without beingrelocated. The elastic support part 54 of the stopper 51 is slightlycompressed by the second pressure projection 72, such that the elasticsupport part 54 is positioned to be movable toward the junction end 52through a gap between the cylinder head 7 and the exhaust hole plate 30.The intermediate point of the stopper 51 between the junction and freeends 52 and 53 is slightly compressed by the third pressure projection73 which does not reach the level of the lower surface 7 a of thecylinder head 7, so that the stopper 51 is supported by the first,second and third pressure projections 71, 72 and 73 while being bentinto the bow shape.

Because the stopper 51 is supported at three points by the first, secondand third pressure projections 71, 72 and 73 of the pressure unit 70while the stopper 51 is bent into the bow shape as described above, thefree end 43 of the reed valve 41 which is placed between the stopper 51and the exhaust hole plate 30 is pre-pressurized by the elastic supportpart 53 of the stopper 51 in a direction toward the exhaust hole plate30, under the condition that the free end 43 of the reed valve 41 ismovable toward the junction end 42.

In the valve assembly, the first and third pressure projections 71 and73 are spaced apart from each other by a distance L1 which is slightlylonger than a distance L2 between the second and third pressureprojections 72 and 73. In other words, the third pressure projection 73is eccentrically positioned between the first and second pressureprojections 71 and 72, such that the third pressure projection 73 isslightly closer to the second pressure projection 72 than the firstpressure projection 71. That is, the third pressure projection 73 whichis placed between the first and second pressure projections 71 and 72,is slightly eccentric toward the second pressure projection 72. Due tothe specific arrangement of the first, second and third pressureprojections 71, 72 and 73, the reed valve 41 closes or opens the exhausthole 31 of the exhaust hole plate 30 at a position slightly closer tothe free end 43 than the junction end 42 of the reed valve 41.Therefore, the reed valve 41 accomplishes less deformation during anoperation of the reed valve 41, in comparison with a conventional valveassembly in which the reed valve closes or opens the exhaust hole at acentral position of the reed valve. The reed valve 41 of the presentinvention thus reduces impact and noise during the operation thereof.Furthermore, the reed valve 41 smoothly opens or closes the exhaust hole31.

The valve assembly 20 for reciprocating compressors according to thepresent invention having the above-mentioned construction is operated,as follows. During an operation of the reciprocating compressor in whichthe piston 6 moves to a lower dead center in the cylinder 4, the reedvalve 41 is pre-pressurized by the elastic support part 54 of thestopper 51 in a direction toward the exhaust hole plate 30, as shown inFIG. 7. The reed valve 41 in the above state thus closes the exhausthole 31.

However, when the piston 6 moves from the lower dead center to an upperdead center in the cylinder 4, a pressure of the gas compressed in thecylinder 4 increases to become higher than the pressure applied to thereed valve 41 from the stopper 51 which has pre-pressurized the reedvalve 41. Therefore, a part of the reed valve 41, which corresponds tothe exhaust hole 31, moves toward the cylinder head 7 as shown in FIG.8, and, at the same time, the free end 43 of the reed valve 41 movestoward the junction end 42 of the reed valve 41. The exhaust hole 31 isthus open.

During the operation to open the exhaust hole 31, the elastic supportpart 54 of the stopper 51, which has pre-pressurized the free end 43 ofthe reed valve 41, slightly moves toward the junction end 52 of thestopper 51 through the gap between the third pressure projection 73 ofthe cylinder head 7 and the exhaust hole plate 30, thus allowing theexhaust hole 31 to be open.

When the piston 6 moves again from the upper dead center to the lowerdead center in the cylinder 4, both the stopper 51 and the reed valve 41restore original shapes thereof. The reed valve 41 thus closes theexhaust hole 31 again, as shown in FIG. 7.

As apparent from the above description, the present invention provides avalve assembly for reciprocating compressors, elements of which areeasily assembled into a single body. In the valve assembly according tothe present invention, a reed valve and a stopper are respectivelyintegrated with a reed valve plate and a stopper plate which are easilyassembled with a cylinder together with a cylinder head by use of aplurality of bolts. The reed valve and the stopper are thus easilyassembled into the valve assembly, thus conserving time and reducingcosts while producing the reciprocating compressors.

In the valve assembly for reciprocating compressors according to thepresent invention, the stopper is compressed at several points thereofby a pressure unit provided on a lower surface of the cylinder head, sothat the stopper is supported while being smoothly bent into a bowshape, and pre-pressurizes a free end of the reed valve. Furthermore,the reed valve opens or closes an exhaust hole while a part of the reedvalve is in contact with the exhaust hole at an intermediate portionbetween the free end and a junction end of the reed valve. Therefore,the valve assembly remarkably reduces impact and noise caused by anoperation of the reed valve while opening or closing the exhaust hole.Furthermore, the reed valve does not vibrate at the free end thereof,thus improving the operational performance of the reciprocatingcompressors.

Furthermore, in the valve assembly of the present invention, the stopperhas an elastic support part at a portion around a free end thereof, thusthe stopper has a sufficient elastic force capable of efficientlypre-pressurizing the reed valve. Therefore, the valve assembly reliablyprevents the reed valve from being undesirably open when a gasrefrigerant is not completely compressed in a compression chamber of acylinder, thus the valve assembly improves operational reliability ofthe reciprocating compressors.

Although a preferred embodiment of the present invention has been shownand described, it would be appreciated by those skilled in the art thatchanges may be made in these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. A valve assembly for reciprocating compressors having a cylinder, acylinder head and a valve assembly arranged between the cylinder andcylinder head, the valve assembly comprising: an exhaust hole platehaving an exhaust hole communicating with the cylinder; a reed valveplate having a reed valve to open or close the exhaust hole of theexhaust hole plate, the reed valve being integrally formed in the reedvalve plate by cutting a predetermined portion of the reed valve plate,with a junction end and a free end formed at first and second ends ofthe reed valve, respectively; a stopper plate having a stopper to limitan opening ratio of the reed valve within a predetermined range, thestopper being integrally formed in the stopper plate by cutting apredetermined portion of the stopper plate, with a junction end and afree end formed at first and second ends of the stopper, respectively,the stopper being bent toward the cylinder head at a predetermined angleof inclination relative to the stopper plate, with an elastic supportpart provided at the free end of the stopper so as to be elasticallysupported by a pressure unit of the cylinder head and provide an elasticforce to the stopper; and the pressure unit provided on a surface of thecylinder head so as to support the stopper and allow the stopper topre-pressurize the reed valve.
 2. The valve assembly according to claim1, wherein the elastic support part is provided by bending the free endof the stopper toward the cylinder head at a predetermined angle ofinclination.
 3. The valve assembly according to claim 2, wherein thepressure unit comprises: a first pressure projection projected from thecylinder head at a position corresponding to the junction end of thestopper, thus compressing the junction end of the stopper; a secondpressure projection projected from the cylinder head at a positioncorresponding to the elastic support part of the stopper, thuscompressing the elastic support part of the stopper; and a thirdpressure projection projected from the cylinder head at a positioncorresponding to an intermediate point of the stopper between thejunction end and the free end of the stopper, thus compressing theintermediate point of the stopper.
 4. The valve assembly according toclaim 3, wherein the second pressure projection is slightly longer thanthe first pressure projection, and the third pressure projection isslightly shorter than the first pressure projection, so that the first,second and third pressure projections support the stopper while bendingthe stopper into a bow shape at a position between the cylinder head andthe exhaust hole plate, and the free end of the reed valve ispre-pressurized by the elastic support part of the stopper which iscompressed by the second pressure projection.
 5. The valve assemblyaccording to claim 4, wherein the third pressure projection iseccentrically positioned between the first and second pressureprojections, and the exhaust hole is formed on the exhaust hole plate ata position corresponding to the third pressure projection.
 6. The valveassembly according to claim 5, wherein the third pressure projection ispositioned to be eccentric toward the second pressure projection.
 7. Thevalve assembly according to claim 6, further comprising: a depressionformed on a surface of the exhaust hole plate at a position around theexhaust hole, so that the reed valve closes the exhaust hole while apart of the reed valve comes into contact with areas of the exhaust holeplate around the exhaust hole and the depression.